[프로그래머스]단어 변환

#include <string>
#include <vector>
#include <queue>
#include <algorithm>
 
using namespace std;
 
bool check[51];
 
int solution(string begin, string target, vector<string> words) {
    int answer = 0;
    
    fill(check, check + 51, false);
    
    queue<pair<string, int>> mainQ;
    mainQ.push( { begin,  0 });
    while (!mainQ.empty()) {
        string word = mainQ.front().first;
        int count = mainQ.front().second;
        mainQ.pop();
        
        if(!word.compare(target)) {
            answer = count;
            break;
        }
        else if(count > words.size()) { 
            break;
        }
        
        for(int idx = 0; idx < words.size(); idx++) {
            if(check[idx]) { continue; }
            int flag = -1;
            for(int i = 0; i < words[idx].size(); i++) {
                if(word[i] != words[idx][i]) { flag++; }
                if(i == words[idx].size() - 1 && !flag) {
                    mainQ.push( { words[idx], count + 1 });
                    check[idx] = true;
                }
            }
        }
    }
    
    return answer;
}